In color printing devices for making color prints from color negative films, the optimum exposure for a color printing is generally determined by measuring the average photographic density of the entire area of a frame, that is, large area transmittance density (LATD). However, in case the subject to be printed contains a "subject failure", the printing method based on the LATD is unfavorable. The automatic color printers currently used in the market are provided with plural push-buttons for correction of density and color balance, and optimum and acceptable printing is achieved by an operator who visually identifies the character of the image to be printed therefrom and accordingly operates such correcting push-buttons.
However, such visual correcting procedure by an operator relies on the personal expertise of the operator and has been a problem in designing a completely automatic color printing machine. It has recently been tried, therefore, to obtain the information on the photographic density of the entire frame by means of a densitometer capable of scanning the entire area of image to be printed therefrom so that automatically estimating the image, specifically finding the presence of the subject failure from the information thus obtained is enabled, whereby printing is conducted in automatic mode to obtain positive image with high quality.